Effect of intrinsic PCB parameters on the performance of fluoropolymer coating under condensing humidity conditions

In this work, Fluoropolymer-based ultrathin coating is evaluated as a protective barrier for Printed Circuit Board (PCB) against corrosion failures. Constant humidity with temperature cycling was applied as external climatic conditions for performance assessment through electrochemical AC impedance and DC potentiostatic measurements. Morphology of the coating before and after test was inspected using Optical, Scanning Electron Microscopy (SEM), and Energy Dispersive Spectroscopy (EDS). Fluoropolymer coating was applied on a PCB interdigitated pattern used as test substrate. The effect of test board cleanliness, coating thickness, and orientation of the PCB placed inside a climatic chamber were investigated with subsequent corrosion morphology observations after climatic exposure. The study showed that the PCB cleanliness as a critical factor controlling performance with less reliance on the orientation of the PCB and the thickness of the coating.